Device for drilling a bore hole in the ground

ABSTRACT

A device for drilling a bore hole in the ground comprised of a rotary drive head and a hollow Connecting Rod Assembly on which the rotary drive head acts and which can be lowered into the hole in the ground through the rotary drive head. A tool head with several Drilling Hammers that work downwards and that are operated with a fluid driving medium are provided on the lower end of the Connecting Rod Assembly. In the case of an initial design form, a Rotary Connecting Head is located in the upper area of the Connecting Rod Assembly; a fluid driving medium under high pressure can be supplied to the upper end of the Connecting Rod Assembly through the rotary connecting head, and the rotary connecting head has a transition chamber in its Housing, sealed in the axial direction towards both sides and connected to an external Supply Line for the fluid operating medium. Several ring seals, grouped in stages in the axial direction and hydraulically pressure-balanced stage-by-stage, are provided in each case on both sides of the transition chamber. In the case of a second design form, the driving is done in an oscillatory fashion around a limited angle, which permits the use of flexible supply lines for the feed-in of scavenging and operating media and the discharge of excavated material.

The invention involves a device for drilling a bore hole. In particular,the device for drilling a bore hole has a drive unit structure to bedrilled in the ground which drive unit structure includes a stationaryrotary drive head.

BACKGROUND OF THE INVENTION

Devices or machines for drilling a bore hole are known from the state ofthe art. The hammer tools are directly connected, several at a time,with the tool head here, so that the impact energy is transferredthrough the driving medium to the hammers plunged down into the borehole. And from these directly to the bore hole floor, so that theconnecting rod assembly remains uninfluenced by this to a great extent.The tool head is connected through the connecting rod assembly with adrive mechanism located outside of the bore hole, like a rotary driveunit, so that the hammers situated on the tool head work on areas of thebore hole floor that are always new. Work is primarily done with thedevices at issue in solid rock.

This type of drilling has increasing significance in practice because,on one hand, the quality of the bore holes is better and the directionof the bore holes can be held on course nearly exactly; on the otherhand, environmental criteria such as noise pollution are kept insignificantly better compliance on the grounds of the sound-absorbingoperating mode in the bore hole without any significant outside effect.

The removal of the rock material that has been hammered loose or scrapedoff from out of the bore hole can be done, in the case of systems ofthis type, within the hollow connecting rod assembly according to theso-called airlift process (reverse circulation). There is, in so doing,a fluid column in the bore hole, and air is blown into the drill columnabove the tool head like a scavenging fluid, so that a difference inpressure arises between the bore hole and the surface in the fluidcolumn in the connecting rod assembly because of the air ascending inthe connecting rod assembly. This difference in pressure induces in theconnecting rod assembly a flow velocity with which the rock material isdischarged through the connecting rod assembly.

When creating a hole in the ground via hammering, the inner diameter ofthe connecting rod assembly, which is available for the removal of theloosened material, has to have a certain minimum size that is adjustedto the total amount to be conveyed up. The rock chunks that are poundedloose also have larger dimensions in comparison to pure rotary drilling.

The fluid driving medium for the drilling hammers seated at the lowerend of the connecting rod assembly is fed to the drilling hammers by thecorresponding rotary connecting head at the upper end of the connectingrod assembly through a feeder constructed in or on the connecting rodassembly.

Problems result with regard to the seals of the rotary connecting headin the case of the relatively large diameters of the connecting rodassembly that are necessary, as mentioned.

Hammers that are driven hydraulically or pneumatically are operated atpressures of around 50 to 150 bar. It turned out that economicaltool-life could not be achieved for the single seals previously used atthe critical point of the transition between the fixed rotary connectinghead and the rotating connecting rod assembly at these high pressuresand with the airlift process requiring large diameters.

The problem involved with the invention is to improve a generic type ofdevice in such a way that the device can be operated with longerrepair-free periods with the larger external diameters of the hollowconnecting rod assembly and the higher pressures that are necessary.

SUMMARY OF THE INVENTION

In accordance with the principal aspect of the present invention, adevice for drilling a bore hole in the ground is provided, wherein thedevice includes a drive unit structure that is located above a bore holeto be drilled in the ground. The drive unit structure includes astationary rotary drive head and a connecting rod assembly. Theconnecting rod assembly is surrounded in a ring-shaped manner by ahousing arranged in an upright fashion as a rule. The fluid drivingmedium, such as air, water or a hydraulic oil, can be fed in by anexternal supply line through a fixed connection leading into thetransition chamber. The transition chamber surrounds the connecting rodassembly in a ring shape here, so that the driving medium is in contactwith the supply line for the operating medium independently of therotary position of the connecting rod assembly. Several ring seals,hydraulically pressure-balanced and grouped in stages in the axialdirection in each case, are provided on both sides of the transitionchamber.

The pressure balancing of the ring seals is chosen in such a way in theoperation of the device that the pressure difference acting on each ringseal does not exceed a maximum value, which is dependent on thecharacteristics of the seal used. On top of this, a pressure is appliedin each case on the side of each ring seal turned away from thetransition chamber in the axial direction that is lower than thepressure applied to the side turned towards the transition chamber. Thedifference in pressure, under the action of which the seal is pressedagainst the external circumference of the connecting rod assembly,corresponds to a value that can be permanently endured by the ring seal.In the case of the outer ring seal in the axial direction, i.e. the ringseal following in the direction pointing away from the transitionchamber, the leading balancing pressure, in the form of an appliedpressure, and a balancing pressure that is lower by an appropriate valueare adjacent; the latter is in turn the balancing pressure for thesubsequent seal. The applied pressures become lower in this way,stage-by-stage; the individual ring seal has to only endure in theprocess a pressure of 10 to 25 bar, for example, which is stillpermissible in each case. An adaptation to the operating pressure of thefluid operating medium can take place through the number of ring sealsused and the balancing pressures chosen.

In one embodiment, the device for drilling a bore hole in the groundincludes a drive unit structure located above the bore hole and having astationary rotary drive head and a hollow connecting rod assembly onwhich the rotary drive head acts and which can be lowered through therotary drive head down into the bore hole, and a first stationary rotaryconnecting head in the drive unit structure. A scavenging medium issupplied to the upper end of the rotating connecting rod assemblythrough the rotary connecting head. The scavenging medium is fed througha first feeder extending along the connecting rod assembly to an inletopening provided on the connecting rod assembly. A second rotaryconnecting head is located in the drive unit structure. A fluidoperating medium under high pressure is supplied to the upper end of theconnecting rod assembly through the second rotary connecting head. Theoperating medium is fed through a second feeder extending along theconnecting rod assembly to the lower end of the connecting rod assembly.The rotary connecting head has a housing surrounding the connecting rodassembly in a ring shape with a transition chamber connected with anouter supply line for the fluid driving medium and with the upper end ofthe second feeder, and sealed towards both sides in the axial direction.A tool head, designed in the form of a flushing head, is located on thelower end of the connecting rod assembly. The tool head is connectedwith the interior of the connecting rod assembly, and with severaldrilling hammers operated with the fluid driving medium, located on thetool head, and operating downwards. Several ring seals grouped in stagesin the axial direction in each case and hydraulically pressure-balancedin stages are provided in the second rotary connecting head on bothsides of the transition chamber.

In accordance with another aspect of the present invention, hydraulicpressures supplied to the ring seals for pressure balancing arepreferably provided by pressure generators, and act in toroidalchambers, that are each located between two ring seals on the sideturned away from the transition chamber. In one embodiment, aring-shaped chamber is located in each case on the side of a ring sealturned away from the transition chamber. The ring-shaped chamber has aconnection for the feed-in of a hydraulic pressure medium and isconnected to a side of the same balancing pressure in the ring seals.

In accordance with yet another aspect of the present invention pumps areused for the generation of the balancing pressures existing in stages.In one embodiment, the pumps are provided as pressure generators.

In accordance with still another aspect of the present invention,pressure reducers in the form of pressure cylinders with one-sidedpressure surface reduction through a piston rod are used as pressurereducers; the driving medium and therefore its pressure can be suppliedto the side of the cylinder having the piston rod, so that a pressurethat is reduced by a fixed percentage relative to the pressure of theoperating medium is forcibly set through the piston rod diameter and theremaining, reduced active area on the other side of the piston. In thecase of the pressure gradation resulting forcibly in this way throughthe geometry of the piston rod, there is an advantage that a variationof the pressure of the operating medium is automatically distributedover the individual pressure differences acting on the individual ringseals, without a readjustment of the individual balancing pressuresbeing necessary. This type of supply of the balancing pressures istherefore independent from the functioning of the pumps and controlvalves. As many pressure reducers are used as there are stages ofbalancing pressure necessary; the differences in the reduced pressuresare generated through differing piston rod diameters. In one embodiment,pressure reducers beset with pressure by the driving medium beingprovided as pressure generators. In another embodiment, the pressurereducers containing cylinders for which the pressure of the drivingmedium can be fed to the piston-rod side of the cylinder, and thepressure generated in the cylinder compartment on the other side of thepiston, through its entire cross section, is reduced in accordance withthe effective surface reduction on the piston-rod side and beingfeedable in each case to an accompanying ring-shaped chamber. In stillanother embodiment, the pressure reducers are located on the fixedhousing of the second rotary connecting head.

The pressure generators can be arranged for practical purposes on thefixed housing of the rotary connecting head, which is simple with regardto the construction aspects and which makes short connection linespossible.

If the stage-by-stage pressure-balancing of the ring seals takes placesymmetrically towards both sides of the transition chamber, two toroidalchambers can always be connected to a pressure reducer.

In accordance with still yet another aspect of the present invention,the rotary driving head of the connecting rod assembly alternatelyrotates forwards and backwards by a limited angle of rotation. The anglewhich the connecting rod assembly, and therefore the tool head, has topass through during every rotation depends on the number of hammers onthe same radius in the tool head. In the case of two hammers on the sameradius, for example, an angle that is passed through of 180° issufficient; it can also be advantageous, however, to rotate the rodassembly by an angle that is larger than the angle that is sufficient.

The advantage of this second design form is that no rotary seals thatare subject to wear are necessary in the supply line for the pressurizedoperating medium to make the rotation of the connecting rod assemblypossible. The connection of the supply line to the feeder can be donethrough flexible tubes, for example, the lengths of which aredimensioned in such a way that the can follow the required angle sweep.The supply line for the fluid driving medium can have a fixed connectionwith the feeder because of the angle of rotation that is limited by thealternating mode of operation. The actual rotary connection for thefluid driving medium with surfaces that rotate against each other,acting on the seals, can be saved. In one embodiment, the device fordrilling a bore hole in the ground causes excavated material to betransported out of the bore hole through the interior of the connectingrod assembly and through an outlet line connected at its upper end. Afirst feeder for leading in a scavenging medium extends up to an inletopening to the interior of the connecting rod assembly and communicateswith the inlet opening. A second feeder through which a fluid operatingmedium, driving excavation tools provided on the tool head and underpressure, is fed to a tool head located at the lower end of theconnecting rod assembly. The rotary drive device drives the connectingrod assembly alternating in the direction of rotation by a limited angleof rotation. The second feeder has a flexible area that makes aconnection with a device for impinging with pressure from thepressurized operating medium.

In accordance with another aspect of the present invention, the feederthat is for guiding the compressed air into the interior of theconnecting rod assembly to lift up the excavated material also has aflexible area which makes the alternating, limited rotary movementpossible. This is because the rotary seal which is also otherwisenecessary for this is saved due to this design arrangement. In oneembodiment, the first feeder has a flexible area that makes a connectionto advice for impinging with pressure from the scavenging medium.

In still another aspect of the present invention, the device cancompletely do without rotary feedthroughs, which are susceptible to wearand which are expensive to manufacture, with the corresponding seals. Inone embodiment, the outlet line has a flexible area that makes thedischarge of the excavation material possible.

In still yet another aspect of the present invention one or both of thesupply lines are designed in the form of flexible tube lines.

In accordance with a further aspect of the present invention, to designthe supply lines are rigid over the length of the connecting rodassembly, to affix it to this and to merely design a short piece of lineleading from these to be flexible.

In accordance with yet a further aspect of the present invention, apower rotary head supported so as to be variable in height on thesupport apparatus and connected with the upper end of the segmentedconnecting rod assembly serves as a rotary drive unit in the case of aninitial design form of this device according to the invention. Theadvance is brought about in the case of this design form through thelowering of the power rotary head. If the power rotary head has reachedits lower position, i.e. the bore hole has been drilled down by asegment length, it has to be released from the upper end of theconnecting rod assembly and subsequently moved into its upper position.A free length exists in this position between the flange serving tofasten the driven part of the power rotary head and the upper end of theconnecting rod assembly; the free length corresponds at a minimum tothat of a segment of the connecting rod assembly. A further segment ofthe connecting rod assembly can now be used. The support apparatus hasto therefore have a height that corresponds at a minimum to the lengthof a segment.

In accordance with another aspect of the present invention the rotarydrive unit is designed, as an alternative, as a rotary drive that isactually constructively familiar from pipework and that can be broughtinto working contact with the surface shell of the connecting rodassembly--through a clamping handle, for example.

In accordance with yet another aspect of the present invention advancingforces can also be led into the connecting rod assembly through therotary drive unit. The advance can take place on the whole through aperiodic "resetting" of the rotary drive unit by relocating it to thetop in the released state by a certain distance, subsequently affixingit again on the surface shell of the connecting rod assembly andlowering it from anew. Because the rotary drive unit can be affixed onnearly any arbitrary point with reference to the length of theconnecting rod assembly, it is no longer necessary that the liftingstroke by which the rotary drive unit can be relocated in the directionof the lengthwise axis of the rod assembly corresponds at a minimum tothe length of a segment of the same, so that the driving device can beconstructed much lower in comparison to the those that are known up tonow.

The height adjustment preferably serves a length-adjustable powergenerator, which is designed in the form of a hydraulically-actuatedpiston/cylinder unit.

In summary, there is provided a device for drilling a bore hole in theground. The device includes a drive unit structure located above thebore hole, a stationary rotary drive head, and a hollow connecting rodassembly on which the rotary drive head acts and which can be loweredthrough the rotary drive head down into the bore hole in the ground. Thedevice also includes a first stationary rotary connecting head in thedrive unit structure, wherein a scavenging medium can be supplied to theupper end of the rotating connecting rod assembly through the firstrotary connecting head. The scavenging medium can be fed through a firstfeeder extending along the connecting rod assembly to an inlet openingprovided on the connecting rod assembly. The device further includes asecond rotary connecting head located in the drive unit structure,wherein a fluid operating medium under high pressure can be supplied tothe upper end of the connecting rod assembly through the rotaryconnecting head. The operating medium can be fed through a second feederextending along the connecting rod assembly to the lower end of theconnecting rod assembly. The rotary connecting head has a housingsurrounding the connecting rod assembly in a ring shape with atransition chamber connected with the outer supply line for the fluiddriving medium and with the upper end of the second feeder, and sealedtowards both sides in the axial direction. A tool head, designed in theform of a flushing head, is located on the lower end of the connectingrod assembly. The tool head is connected with the interior of theconnecting rod assembly, and with several drilling hammers to operatewith the fluid driving medium, located on the tool head, and operatingdownwards. Several ring seals, grouped in stages in the axial directionin each case and hydraulically pressure-balanced in stages, are providedin the second rotary connecting head on both sides of the transitionchamber. Preferably, a ring-shaped chamber is located on the side of aring seal and turned away from the transition chamber. The ring-shapedchamber has a connection for the feed-in of a hydraulic pressure mediumand is connected to a side of the same balancing the pressure in thering seals. Preferably, pumps are provided as pressure generators. Morepreferably, pressure reducers beset with pressure by the driving mediumare provided as pressure generators. Even more preferably, the pressurereducers contain cylinders for which the pressure of the driving mediumcan be fed to the piston-rod side of the cylinder, and the pressuregenerated in the cylinder compartment on the other side of the piston,through its entire cross section, is reduced in accordance with theeffective surface reduction on the piston-rod side and being feedable ineach case to an accompanying ring-shaped chamber. Still even morepreferably, the pressure reducers are located on the fixed housing ofthe second rotary connecting head. Preferably, the stage-by-stagepressure-balancing of the ring seals takes place symmetrically towardsboth sides of the transition chamber. Preferably, a hollow connectingrod assembly and a first feeder is provided for leading in thescavenging medium. The feeder extends up to an inlet opening to theinterior of the connecting rod assembly and communicates with theinterior of the connecting rod assembly. A second feeder is providedthrough which a fluid operating medium, driving excavation toolsprovided on the tool head and under pressure, can be fed to a tool headlocated at the lower end of the connecting rod assembly.

The rotary drive device driving the connecting rod assembly alternate inthe direction of rotation by a limited angle of rotation. The secondfeeder has a flexible area that, when the alternatingrotational-direction movement occurs, makes a connection with a devicefor impinging with pressure from the pressurized operating medium.Preferably, the first feeder has a flexible area that, when thealternating rotational-direction movement occurs, makes a connection toa device for impinging with pressure from the scavenging medium.Preferably, the outlet line has a flexible area that, when thealternating rotational-direction movement occurs, makes the discharge ofthe excavation material possible. Preferably, one or both supply linesare designed as flexible tube lines. Preferably, the lines are designedso as to be rigid in the area of the connecting rod assembly and beingaffixed to this. Preferably, a power rotary head located at the upperend of the connecting rod assembly, supported so as to be variable inheight on the support apparatus, serves as a rotary drive device.Preferably, a rotary drive unit, actually known constructively frompipework devices, which can as a choice be brought into active contactwith the connecting rod assembly, being provided as a rotary drivedevice. Preferably, the rotary drive unit is located on the supportapparatus so as to be adjustable in height. Preferably,length-adjustable power generators serving the height adjustment.Preferably, the length-adjustable power generator is designed ashydraulically-activated piston and/or cylinder units.

Further design arrangements of the invention can be found in thefollowing description with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following are shown in the drawing:

FIG. 1 shows, in perspective, a drive unit construction, located outsideof the bore hole in the ground, of an initial design form according tothe invention;

FIG. 1A shows a rotary drive unit, which can be used as an alternativeto the rotary drive presented here in the case of the design form of thedrive unit in accordance with FIG. 1;

FIG. 2 schematically shows the mode of operation of the airlift systemfor the device according to the invention;

FIG. 3 shows the rotary connecting head for the fluid operating mediumin a side view, partially as a sectional view;

FIG. 4 shows a lengthwise section going through the longitudinal axisthrough the upper part of the rotary connecting head depicted in FIG. 3in an enlarged scale:

FIG. 4A shows an enlarged rendering of the area bordered by adot-and-dash pattern, designated in FIG. 4 with IVa;

FIG. 5 schematically shows sectional views of three pressure reducerswith different piston rod diameters;

FIG. 6 shows a side view of a tool head with several drilling hammers;

FIG. 7 shows a view in accordance with FIG. 6 from the bottom;

FIG. 8 shows, in perspective, a view corresponding to FIG. 1 of a seconddesign form according to the invention;

FIGS. 9 and 10 show two further design forms of the device according tothe invention in a view corresponding to FIG. 8 and

FIG. 11 shows an oscillation drive, as it can be used in the design inaccordance with FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the part of a device according to the invention of theinitial design form located outside of a to-be-drilled hole in theground. The drive construction of the device, designated overall with 3,is fastened to a Support Apparatus 2, which is supported on an operatingdesignated overall with 1. A Rotary Drive Head 4, schematically shown,acts on a Connecting Rod Assembly 5 having segments that can beconnected with each other, of which only the upper part is shown andwhich (only indicated with a dotted line) extends through the OperatingPlatform 1 into the to-be-drilled hole in the ground and up to the toolhead. The driving of the Connecting Rod Assembly 5 with the RotaryConnecting Head 4 can be done in a customary manner, known from thestate of the art, through a hydraulic motor for example.

It is alternatively possible, however, to use a Rotary Drive Unit 4'depicted in FIG. 1A, as it is actually constructively familiar frompipework devices, instead of the Rotary Drive Head 4 located at theupper end of the Connecting Rod Assembly 5.

This Rotary Drive Unit 4' a fixed, external Part 4" opposite to whichthere is a ring-shaped Inner Part 4'" that can be rotary driven, theinner diameter of which is adapted to the external diameter of theConnecting Rod Assembly 5 and with which a connection can alternately bemade at least in the driving direction in an active connection, i.e.non-positive or positive-locking. The driving can take place, forexample through a hydraulic motor. The Rotary Drive Unit 4'length-variable Power Generators 2' on the Support Apparatus 2, such asspindles or piston/cylinder units for example, can be in an activeconnection with its fixed Part 4". If the Connecting Rod Assembly 5 andthe Inner Part 4'" of the Rotary Drive Unit 4' are designed in such away that a positive-locking connection between this and the Inner Part4'" can even be achieved in the lengthwise direction of the ConnectingRod Assembly 5, an advancing force can be led into the connecting rodassembly through the Rotary Drive Unit 4', so to speak. It is likewisepossible, however, to support the Rotary Drive Unit 4' in a fixed manneron the support apparatus and design the Inner Part 4'" and theConnecting Rod Assembly 5 in such a way that the Connecting Rod Assembly5 can be displaced in its lengthwise direction in the Inner Part 4'". Inthis case, the advancing forces are to be led into the connecting rodassembly by acting, for example, on the first Rotary Connecting Head 10still to be described.

A first rotary connecting head, designated with 10, is located at theupper end of the Connecting Rod Assembly 5. The material loosened at thebase of the hole in the ground is carried off to the outside through therotary connecting head through the Outlet Pipe 21, and compressed air isled into the connecting rod assembly by means of a first Supply Line 13.A second rotary connecting head, designated overall with 20, is locatedbeneath the first Rotary Connecting Head 10. The Support Apparatus 2 canbe swiveled around a Horizontal Axis A and is connected with SwivelDrives 6, so that it can be tilted, and holes in the ground can also bebored that deviate from the vertical direction.

FIG. 2 schematically explains the process with which chunks of soilloosened with the Hammers 41 of the Tool Head 40 from the Floor 16 ofthe Hole in the Ground 9, partially filled with water, for example, upto a Level 9' are transported to the outside. The interior area of theConnecting Rod Assembly 5 forms a Scavenging Pipe 8 that is normallyfilled with water, into which air is blown in above the Tool Head 40through an Inlet Flap 43. The air was compressed outside of the boringdevice with a compressor that is not shown and is guided downwardsthrough a first Supply Line 13 and the first Rotary Connecting Head 10by means of a first Feeder 12 along the Connecting Rod Assembly 5. Theair that is blown in brings about an upwards flow within the ScavengingPipe 8 through the difference in density between the liquid inScavenging Pipe 8, which is interspersed with air bubbles, and theexternal liquid in the Hole in the Ground 9. The Soil Chunks 7 aretransported up with the upwards flow and are scavenged out of the devicethrough the Outlet Pipe 11. The operating medium is fed through a secondSupply Line 23 in the second Connecting Head 20 of the second Feeder 22,shown in one piece with the first connecting head, and is led downwardsthrough this along the Connecting Rod Assembly 5 to the drive unit ofthe Hammers 41 of the Tool Head 40.

FIG. 3 shows a side view of the second Pressure Connection Head 20; theleft half in the view is reproduced and the right half shows a sectionthrough the second Rotary Connecting Head 20, going through Axis B ofthe Connecting Rod Assembly 5, for leading the operating medium into thesecond Feeder 22. Located within the Housing 24 are the staggered sealarrangements, the manner of operation of which will be described furtherbelow, and the Pivot Bearings 32, on which the Housing 24 is supportedin a rotatable fashion on the external periphery of the Connecting RodAssembly 5. The second Rotary Connecting Head 20 can be fastened througha Torsion Stay 25, for example, to the Support Apparatus 2 from FIG. 1.This fastening can be brought about by means of bolts that, if thesecond Rotary Connecting Head 20 is to also turn, only have to beunlatched. If the device according to the invention is to namely only beused for pure rotary drilling in the meantime, the detaching of theHousing 24 of the second Rotary Connecting Head 20 surrounding theConnecting Rod Assembly 5 serves the purpose that the second RotaryConnecting Head 20 can also turn after detaching the supply line for thefluid operating medium, so that the ring seals in this state are neitherhydraulically nor mechanically stressed; the serviceable life isextended because of this.

Three Pressure Reducers 50 are fastened to the fixed Housing 24 in theexample shown; their function will still be explained in more detail.

FIG. 4 shows a section through the second Rotary Connecting Head 20. Theoperating medium for driving the hammers--water is preferably used forenvironmental reasons and operating-technology reasons--is fed through afixed Connection 26, to which the second Supply Line 23 (FIG. 2) isconnected, to a Transition Chamber 27, which surrounds the ConnectingRod Assembly 5 in a ring shape. The surface of the Connecting RodAssembly 5 should be smooth and even to the extent possible in the areaof the second Rotary Connecting Head 20, so that the seals lying againstit are not excessively strained with regard to wear and tear. Theoperating medium goes from the Transition Chamber 27 on the first Feeder12, intersecting the Rotary Drive Head 20, for the scavenging mediumonwards through Blow-By Openings 14 distributed over the periphery intoa Toroidal Chamber 15 constructed on the upper end of the Connecting RodAssembly 5, and from there into the second Feeder 22, in the form of apipe, running along the outside of the Connecting Rod Assembly 5. TheFeeder 12 is also a pipe running along the outside of the connecting rodassembly. The two Feeders 12 or 22, as the case may be, and theScavenging Pipe 8 are therefore separated from each other.

The Housing 24 has an upper Flange 28 and a lower Flange 29, betweenwhich the Transition Chamber 27 for the operating medium is constructedin the second Feeder 22. Four ring seals, designated with 30a, 30b, 30cand 30d and grouped in stages one behind the other in the axialdirection, are located on both sides of the Transition Chamber 27; thering seals have a roughly L-shaped cross section in the design example.The one Leg 35' each ring seal (FIG. 4A) acts against the TransitionChamber 27 carrying the high pressure and is adjacent to the outer sideon the rotating External Periphery 5' of the Connecting Rod Assembly 5.The other Leg 35" in each case extends outwards in a plane that isvertical to the axis of the Connecting Rod Assembly 5. The Legs 35" areeach located between neighboring Rings 34a, 34b, 34c, 34d, which arehoused in a cylindrical Chamber 36 of the housing neighboring on theExternal Periphery Surface 5' and pulled together with the Legs 35"located in between into a packet or block, so that all of the ring sealsare fastened.

The Rings 34a, 34b, 34c, 34d leave ring-shaped Chambers 38a, 38b, 38c,38d, for seating the Legs 35' of the ring seals, on their innerperiphery surface turned towards the External Periphery Surface 5'. Thering-shaped Chambers 38a, 38b, 38c each have their own Connection 39a,39b, 39c through which a pressure medium can be fed by a PressureReducer 50. The pressure medium fed to the respective ring-shapedChambers 38a, 38b, 38c goes through the slot between the inner peripheryof the neighboring ring turned towards the Transition Chamber 27 and theExternal Periphery Surface 5' to the back side of the next ring sealcloser to the Transition Chamber 27.

The pressure gets, for example, in the ring-shaped Chamber 38c, to theBack Side 31d of the Leg 35' of the Ring Seal 30d and seeks to lift thisup from the External Periphery Surface 5'. In the case of 17, the liquidthat is under pressure penetrates into the ring-shaped Chamber 38d andpresses the Leg 35' onto the External Periphery Surface 5. The pressureprevailing in the ring-shaped Chamber 38c acts against the pressure. Thedifference in pressure is controlling for the actual existing pressure.The pressure in the Connection 39c is selected in such a way that theactive difference in pressure does not exceed a certain limit value inthe range of around 10 to 25 bar, which the Ring Seal 30d permanentlyendures.

The pressure applied to the Connection 39c presses the Leg 35 of theRing Seal 30c against the External Periphery Surface 5c. This pressureis generally too high for the Ring Seal 30c. A lower pressure istherefore applied to the Connection 39b; the lower pressure acts on theOutside 31c of the Leg 35' of the Ring Seal 30c so as to relievepressure, so that the latter is not endangered. In the case of the nextRing Seal 30b, the pressure relief takes place with the pressure appliedto the Connection 39a, which no longer endangers the Ring Seal 30a. Thehigh pressure in the Transition Chamber 27 is dissipated in stages inthis way, so that the Leg 35' is only pressed against every ring sealwith a partial pressure that is not dangerous for it.

As already mentioned, Bearings 32 are located within the Housing 24, onwhich the Connecting Rod Assembly 5 can rotate within the fixed Housing24 and that hold the ring seals radially in a defined position vis-a-visthe External Periphery Surface 5' of the connecting rod assembly formingthe pressure surface. A moment of friction is transferred from therotating External Periphery Surface 5' through the Ring Seals 30a, 30b,30c 30d to the Housing 24, which is collected by the Torsion Stay 25that has likewise already been mentioned.

The design form shown has been designed, for example, for a pressure ofan operating medium of around 70 bar. The first ring-shaped Chamber 38dis beset with a pressure that comes to approx. 85% of the pressure ofthe operating medium in the Transition Chamber 27. The secondring-shaped Chamber 38c is beset with a pressure that comes to approx.50% and the third ring-shaped Chamber 38b with a pressure that comes toapproximately 15% of the pressure of the operating medium. It followsfrom this that the difference in pressure on the first Ring Seal 30dcomes to approx. 10 bar, on the second and third Ring Seals 30b and 30caround 25 bar each and on the fourth Seal 30d around 10 bar again. Nowear and tear that is too high arises at these pressures despite thelarge external periphery of the Connecting Rod Assembly 5 and aperipheral speed of 5 to 20 m generated on the External PeripherySurface 5' by the rotary drive head; experience has shown that this highwear and tear is unavoidable if only one seal is under the entirepressure in the Transition Chamber 27.

Depending on the pressures of the operating medium, the number of ringseals can be varied, but always in such a way that the difference inpressure on the individual ring seal does not exceed a limit value of 25bar, for example.

The pressure-balancing of the individual Ring Seals 30d, 30c, 30b iscontrolled in a fixed dependence by the pressure of the operating mediumover the geometry of the individual Pressure Reducers 50. FIGS. 5A, 5Band 5C show the structure of three Pressure Reducers 50A, 50B and 50Cdesigned in the form of Hydraulic Cylinders 56. The Cylinders 56 eachhave a Head Plate 55 and a Floor Plate 57, as well as a Piston Rod 51A,51B and 51C of different diameters D reaching through the Head Plate 55,but the same Pistons 53 and Cylinder Chambers 54 of the same diameterclosed up to the Connections 58 in the Floor Plate 57. The operatingmedium is fed to the Cylinder 56 in each case through a Connection 52 onthe piston rod side, i.e. in the Head Plate 55. The Cylinder Chamber 54is filled with a hydraulic medium differing from the operating mediumand is connected with a Connection 39a, 39b, 39c of a Toroidal Chamber38a, 38b, 38c through the Connection 58 and hydraulic lines. If thediameter of the Cylinder Chambers 54 and the Piston 53 is the same forall of the Pressure Reducers 50 that are used, the pressure in thering-shaped Chambers 38a, 38b, 38c generated with the Pressure Reducers50 is only determined by the residual cross section of the CylinderChamber 54 remaining after taking away the cross section of the pistonrod. The Pressure Reducer 50A with the smallest piston rod cross sectiontherefore generates the highest pressure. It is connected to thering-shaped Chamber 38c.

The hydraulic medium in the Cylinder Chambers 54 and the ring-shapedChambers 38a, 38b, 38c is preferred as a lubricant, e.g. a grease, whichlubricates the Ring Seals 30a, 30b, 30c, 30d. The ring seals consist ofan elastomer material.

A Tool Head 40 is shown in FIGS. 6 and 7, which is provided, forexample, for driving with water as the operating medium. The Hammers 41driven by the operating medium are connected with a Mounting Plate 42through Supports 44; the mounting plate is attached at the lower end ofthe Connecting Rod Assembly 5. The Tools 45 arranged on the Hammers 41act downwards on the Floor 10 of the Hole in the Ground 9 (FIG. 2) andsmash the rock there. The respective point of action moves along throughthe rotation of the Tool Head 40 in the direction of the periphery. Theentire cross section of the bore hole can be swept over through theattachment of the Tools 45 at difference radii. The number andarrangement of the Tools 45 can be adapted to the diameter of the Holein the Ground 9 and the material to be excavated. The Hammers 41 areheld and guided on their lower ends on a circular disk-shaped GuidePlate 46 of a diameter corresponding to the diameter of the hole in theground.

FIG. 8 shows a second design form. Parts that are appropriate for eachothers' functions are provided with reference signs increased by 100.The basic structure corresponds to a great degree to that of FIG. 1. Thedescription there is applicable to that extent for the design form atissue.

The drive unit structure of the device, designated overall with 103, isfastened to a Support Apparatus 102, which is supported on an operatingplatform designated overall with 101. A Rotary Drive Head 104, which isschematically shown, acts on a Connecting Rod Assembly 105 that extendsthrough the Operating Platform 101 into the hole in the ground to bedrilled and up to the tool. The driving of the Connecting Rod Assembly105 by means of the Rotary Drive Head 104 can take place in a customarymanner that is known from the state of the art.

A first connecting head, designated with 110, is located at the upperend of the Connecting Rod Assembly 105; the material loosened on thefloor of the hole in the ground is carried away to the outside throughthe connecting head through the Outlet Pipe 121, and a scavenging fluid,usually air, is led in by means of a first Supply Line 113 in theConnecting Rod Assembly 105. A second connecting head, designatedoverall with 120, is located beneath the first Connecting Head 110. TheSupport Apparatus 102 can be tilted around a Horizontal Axis A by meansof Swivel Drives 106, so that holes in the ground that deviate from thevertical can also be drilled.

In the case of the second design form of the invention, the secondConnecting Head 120 can also rotate as a whole with the Connecting RodAssembly 105, and only the first Rotary Connecting Head 100 is mountedso as to be stationary. The Rotary Drive Head 104 is designed in such away that it rotates the Connecting Rod Assembly 105, together with thesecond Connecting Head 120 for the driving medium of the hammers in thetool, back and forth in an oscillatory motion by a predetermined anglearound the rotational axis of the Rod Assembly 105. This angle that isswept through is under 360°, as a rule, and is chosen in dependence onthe number and the position of the Hammers 41 lying on the same radius(FIGS. 6 and 7). When there is only one Hammer 41 per radius, 360° arerequired; in the case of two hammers per radius displaced by 180° toeach other, a back-and-forth rotation of 180° suffices. It is likewisewithin the framework of the invention, though, to rotate the tool headback and forth by a limited angle that is, however, larger than 360°.

Because of the limited angle of rotation, it is possible to work with asupply line for the driving medium that is installed in a stationarymanner and that goes along with the angle of rotation, without requiringa rotary seal. In the design example shown, the driving medium is ledinto the second Feeder 122 of the Connecting Rod Assembly 105 by meansof a flexible Tube 115. The Tube 115 is mounted between the secondSupply Line 123 and the second Feeder 122. The length of the Tube 115 ischosen in such a way that the Tube 115 can follow the rotation of theConnecting Rod Assembly 105 without obstructing it.

In the case of a further design form, depicted in FIG. 9, for whichparts that are appropriate for each others' functions are provided withreference signs increased by 200 vis-a-vis FIG. 1, the Supply Line 223for the operating medium, the Supply Line 213 for the aeration and theOutlet Pipe 221 are designed as flexible tubes. The two Supply Lines 213and 223 are connected with the Lines 212, 222 running on the ConnectingRod Assembly 205 through flange arrangements not depicted individuallybeneath the Rotary Drive Unit 204 at the Points 213',223'. Thecompressed air of the inlet opening (43 in FIG. 2) or, as the case maybe, the operating medium is fed to the tool head (40 in FIG. 2) throughthe lines (running on the connecting rod assembly). The advantage ofthis design form consists in the Rotary Drive Head 204, which onlybrings about an oscillatory movement in this case, having to onlycontain a pivot bearing for the Connecting Rod Assembly 205; rotaryfeedthroughs and rotary seals can, however, be done without entirely.

It is to be pointed out in connection with this that it is notabsolutely necessary to connect the flexible Tubes 213, 223 with theLines 212, 222 at the Points 213' and 223'. It is rather within theframework of the invention as well to completely do without the rigidLines 212, 222, and to lead the Tubes 213, 223 up to the correspondingconnection points lying in the bore hole on the connecting rod assemblyor on the tool head.

Instead of the Rotary Drive Head 204 continually acting on the upper endof the upper segment of the Connecting Rod Assembly 205, it is alsopossible in the case of this design form to provide a Rotary Drive Unit4', which acts externally on the Connecting Rod Assembly 205 and theoperating mode and functioning of which also otherwise correspond tothose of Rotary Drive Unit 4', but which merely brings about aback-and-forth movement of the connecting rod assembly.

The Rotary Drive Unit 304' depicted in FIG. 11, which is actually knownfrom pipework machines and should therefore not be described in detailany longer, contains a Part 304'", which can be put into oscillatorymovement with the aid of two piston/cylinder units and which is designedto be able to be swung open in multiple parts over its periphery. ThePart 304'" slid onto this is closed for coupling to the Connecting RodAssembly 305, so that it is in the effective direction of the cut withthe surface shell of the Connecting Rod Assembly 205.

A further design form of the device according to the invention isdepicted in FIG. 10. Parts that are appropriate for each others'functions are provided with reference signs increased by 300 regardingthe design form in FIG. 1. An upper bearing arrangement within theframework of the Rotary Drive Unit 204 in FIG. 9 or of a rotaryconnecting head is completely done without for this. A Drive Unit 304serves the oscillation drive; the drive unit corresponds in its functionto the one depicted in FIG. 11 and described above.

The connection of the Tube Lines 313, 323 with the Feeders 312, 322 orof the Tube Line 321 with the interior of the Connecting Rod Assembly305 is done with the aid of the Flange Head 360, located at the upperend of the upper segment of the connection mount, which is designed insuch a way that connections provided on this for the Tube Lines 313,323, 321 communicate with the Lines 312, 322 or the interior of theconnecting rod assembly.

The Drive Unit 304 is supported on the Support Unit 302 throughlength-adjustable power generators 302', so that the advancing force canalso be led through the Drive Unit 304 into the connecting rod assemblythrough a lowering of the Drive Unit 304. If the Drive Unit 304 hasreached its lower position, a further advance can be brought aboutthrough "remounting", by loosening it and setting it in place again,after it has been moved into a higher position with the aid of the powergenerator, and the process begins from anew. Because no support unit,the length of which corresponds to at least that of a segment of theConnecting Rod Assembly 5, is required for this device, this design formdistinguishes itself by a particularly low overall height.

What is claimed is:
 1. A device for drilling a bore hole in the groundcomprising:a drive unit structure to be located above the bore hole, astationary rotary drive head, a hollow connecting rod assembly on whichthe rotary drive head acts and which can be lowered through the rotarydrive head down into the bore hole in the ground, a first stationaryrotary connecting head in the drive unit structure; a scavenging mediumbeing supplied to an upper end of the connecting rod assembly throughthe first rotary connecting head; the scavenging medium being fedthrough a first feeder extending along the connecting rod assemble to aninlet opening provided on the connecting rod assembly; a second rotaryconnecting head located in the drive unit structure, a fluid operatingmedium under high pressure being supplied to the upper end of theconnecting rod assembly through the second rotary connecting head, thefluid operating medium being fed through a second feeder extending alongthe connecting rod assembly to a lower end of the connecting rodassembly, and the second rotary connecting head having a housingsurrounding the connecting rod assembly in a ring shape with atransition chamber connected with an outer supply line for said fluidoperating medium and with an upper end of the second feeder, and sealedtowards both sides in the axial direction, a tool head in the form of aflushing head, located on the lower end of the connecting rod assembly;the tool head being connected with the interior of the connecting rodassembly; a plurality of drilling hammers operated with said fluidoperating medium, located on the tool head, and operating downwards, anda plurality of ring seals, grouped in stages in the axial direction andhydraulically pressure-balanced in stages, the ring seals being providedin the second rotary connecting head on both sides of the transitionchamber.
 2. The device of claim 1, wherein a stage-by-stagepressure-balancing of said ring seals taking place symmetrically towardsboth sides of said transition chamber.
 3. The device of claim 1,including a ring-shaped chamber being located on the side of said ringseals and turned away from the transition chamber; the ring-shapedchamber having a connection for the feed-in of a hydraulic pressuremedium and being connected to a side of the same balancing the pressurein said ring seals.
 4. The device of claim 3, including pumps beingprovided as pressure generators.
 5. The device of claim 4, wherein astage-by-stage pressure-balancing of said ring seals taking placesymmetrically towards both sides of said transition chamber.
 6. Thedevice of claim 3, wherein a stage-by-stage pressure-balancing of saidring seals taking place symmetrically towards both ides of saidtransition chamber.
 7. The device of claim 3, including pressurereducers beset with pressure by the driving medium being provided aspressure generators.
 8. The device of claim 7, wherein said pressurereducers are located on the fixed housing of the second rotaryconnecting head.
 9. The device of claim 7, wherein said pressurereducers contain cylinders for which the pressure of said fluidoperating medium can be fed to a piston-rod side of the cylinder, andthe pressure generated in a cylinder compartment on the other side ofthe piston, through its entire cross section, being reduced inaccordance with the effective surface reduction on a piston-rod side andbeing feedable in each case to an accompanying ring-shaped chamber. 10.The device of claim 9, wherein said pressure reducers are located on thefixed housing of the second rotary connecting head.
 11. The device ofclaim 10, wherein a stage-by-stage pressure-balancing of said ring sealstaking place symmetrically towards both sides of said transitionchamber.
 12. A device for drilling a bore hole in the groundcomprising:a drive unit structure to be arranged above the bore hole tobe drilled in the ground, having a rotary drive device, a hollowconnecting rod assembly on which the rotary drive device acts and whichcan be lowered into the hole in the ground, said connecting rod assemblyallowing excavated material to be transported out of the bore holethrough the interior of the connecting rod assembly and through anoutlet line connected at an upper end of said connecting rod assembly, afirst feeder for leading in a scavenging medium, the first feederextending up to an inlet opening leading to the interior of saidconnecting rod assembly, a second feeder through which a fluid operatingmedium can be fed to a tool head located at a lower end of saidconnecting rod assembly, said fluid operating medium being pressurizedand driving excavation tools provided on a tool head, said rotary drivedevice driving the connecting rod assembly, alternating in the directionof rotation, by a limited angle of rotation and said second feederhaving a flexible area that, when the alternating rotational-directionmovement is made possible, connects said second feeder with a device forimpinging with pressure from the pressurized fluid operating medium. 13.The device of claim 12, wherein said first feeder has a flexible areathat, when the alternating rotational-direction movement is madepossible, connects said first feeder to a device for impinging withpressure from the scavenging medium.
 14. The device of claim 13, whereinthe outlet line has a flexible area that, when the alternatingrotational-direction movement is made possible, allows the discharge ofsaid excavation material.
 15. The device of claim 14, wherein one orboth supply lines is a flexible tube line.
 16. The device of claim 15,wherein said supply lines are rigid in the area connected to theconnecting rod assembly.
 17. The device of claim 16, including a powerrotary head located at said upper end of the connecting rod assembly,said power rotary head being supported by a support apparatus so as tobe variable in height on the support apparatus, said rotary head servingas a rotary drive device.
 18. The device of claim 17, including a rotarydrive positioned in active contact with said connecting rod assembly,said rotary drive unit being provided as a rotary drive device.
 19. Thedevice of claim 18, wherein said rotary drive unit is located on saidsupport apparatus so as to be adjustable in height.
 20. The device ofclaim 19, including length-adjustable power generators serving theheight adjustment.
 21. The device of claim 20, wherein saidlength-adjustable power generator includes hydraulically-activatedpiston/cylinder units.
 22. The device of claim 12, wherein said supplylines are rigid in the area connected to the connecting rod assembly.23. The device of claim 22, including a power rotary head located atsaid upper end of the connecting rod assembly, said power rotary headbeing supported by a support apparatus so as to be variable in height onthe support apparatus, said rotary head serving as a rotary drivedevice.
 24. The device of claim 23, including a rotary drive positionedin active contact with said connecting rod assembly, said rotary driveunit being provided as a rotary drive device.
 25. The device of claim12, wherein one or both supply lines is a flexible tube line.
 26. Thedevice of claim 12, wherein the outlet line has a flexible area that,when the alternating rotational-direction movement is made possible,allows the discharge of said excavation material.
 27. The device ofclaim 25, wherein one or both supply lines is a flexible tube line. 28.The device of claim 27, wherein said supply lines are rigid in the areaconnected to the connecting rod assembly.
 29. The device of claim 28,including a power rotary head located at said upper end of theconnecting rod assembly, said power rotary head being supported by asupport apparatus so as to be variable in height on the supportapparatus, said rotary head serving as a rotary drive device.
 30. Thedevice of claim 29, including a rotary drive positioned in activecontact with said connecting rod assembly, said rotary drive unit beingprovided as a rotary drive device.
 31. The device of claim 12, includinga rotary drive unit positioned in active contact with said connectingrod assembly, said rotary drive unit being provided as a rotary drivedevice.
 32. The device of claim 31, wherein said rotary drive unit islocated on said support apparatus so as to be adjustable in height. 33.The device of claim 32, including length-adjustable power generatorsserving the height adjustment.
 34. The device of claim 33, wherein saidlength-adjustable power generator includes hydraulically-activatedposition/cylinder units.
 35. The device of claim 12, including a powerrotary head located at said upper end of the connecting rod assembly,said power rotary head being supported by a support apparatus so as tobe variable in height on the support apparatus, said rotary head servingas a rotary drive device.
 36. The device of claim 35, including a rotarydrive positioned in active contact with said connecting rod assembly,said rotary drive unit being provided as a rotary drive device.
 37. Thedevice of claim 12, wherein said supply lines are rigid in the areaconnected to the connecting rod assembly.
 38. The device of claim 37,including a power rotary head located at said upper end of theconnecting rod assembly, said power rotary head being supported by asupport apparatus so as to be variable in height on the supportapparatus, said rotary head serving as a rotary drive device.
 39. Thedevice of claim 38, including a rotary drive positioned in activecontact with said connecting rod assembly, said rotary drive unit beingprovided as a rotary drive device.